/*
** $Id: lvm.c,v 2.268 2016/02/05 19:59:14 roberto Exp $
** Lua virtual machine
** See Copyright Notice in lua.h
*/

#define lvm_c
#define LUA_CORE

#include "lprefix.h"

#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lvm.h"


/* limit for table tag-method chains (to avoid loops) */
#define MAXTAGLOOP  2000



/*
** 'l_intfitsf' checks whether a given integer can be converted to a
** float without rounding. Used in comparisons. Left undefined if
** all integers fit in a float precisely.
*/
#if !defined(l_intfitsf)

/* number of bits in the mantissa of a float */
#define NBM     (l_mathlim(MANT_DIG))

/*
** Check whether some integers may not fit in a float, that is, whether
** (maxinteger >> NBM) > 0 (that implies (1 << NBM) <= maxinteger).
** (The shifts are done in parts to avoid shifting by more than the size
** of an integer. In a worst case, NBM == 113 for long double and
** sizeof(integer) == 32.)
*/
#if ((((LUA_MAXINTEGER >> (NBM / 4)) >> (NBM / 4)) >> (NBM / 4)) \
    >> (NBM - (3 * (NBM / 4))))  >  0

#define l_intfitsf(i)  \
  (-((lua_Integer)1 << NBM) <= (i) && (i) <= ((lua_Integer)1 << NBM))

#endif

#endif



/*
** Try to convert a value to a float. The float case is already handled
** by the macro 'tonumber'.
*/
int luaV_tonumber_( const TValue* obj, lua_Number* n ) {
    TValue v;

    if ( ttisinteger( obj ) ) {
        *n = cast_num( ivalue( obj ) );
        return 1;
    }
    else if ( cvt2num( obj ) &&   /* string convertible to number? */
              luaO_str2num( svalue( obj ), &v ) == vslen( obj ) + 1 ) {
        *n = nvalue( &v ); /* convert result of 'luaO_str2num' to a float */
        return 1;
    }
    else {
        return 0;    /* conversion failed */
    }
}


/*
** try to convert a value to an integer, rounding according to 'mode':
** mode == 0: accepts only integral values
** mode == 1: takes the floor of the number
** mode == 2: takes the ceil of the number
*/
int luaV_tointeger( const TValue* obj, lua_Integer* p, int mode ) {
    TValue v;
again:

    if ( ttisfloat( obj ) ) {
        lua_Number n = fltvalue( obj );
        lua_Number f = l_floor( n );

        if ( n != f ) { /* not an integral value? */
            if ( mode == 0 ) {
                return 0;    /* fails if mode demands integral value */
            }
            else if ( mode > 1 ) { /* needs ceil? */
                f += 1;    /* convert floor to ceil (remember: n != f) */
            }
        }

        return lua_numbertointeger( f, p );
    }
    else if ( ttisinteger( obj ) ) {
        *p = ivalue( obj );
        return 1;
    }
    else if ( cvt2num( obj ) &&
              luaO_str2num( svalue( obj ), &v ) == vslen( obj ) + 1 ) {
        obj = &v;
        goto again;  /* convert result from 'luaO_str2num' to an integer */
    }

    return 0;  /* conversion failed */
}


/*
** Try to convert a 'for' limit to an integer, preserving the
** semantics of the loop.
** (The following explanation assumes a non-negative step; it is valid
** for negative steps mutatis mutandis.)
** If the limit can be converted to an integer, rounding down, that is
** it.
** Otherwise, check whether the limit can be converted to a number.  If
** the number is too large, it is OK to set the limit as LUA_MAXINTEGER,
** which means no limit.  If the number is too negative, the loop
** should not run, because any initial integer value is larger than the
** limit. So, it sets the limit to LUA_MININTEGER. 'stopnow' corrects
** the extreme case when the initial value is LUA_MININTEGER, in which
** case the LUA_MININTEGER limit would still run the loop once.
*/
static int forlimit( const TValue* obj, lua_Integer* p, lua_Integer step,
                     int* stopnow ) {
    *stopnow = 0;  /* usually, let loops run */

    if ( !luaV_tointeger( obj, p,
                          ( step < 0 ? 2 : 1 ) ) ) { /* not fit in integer? */
        lua_Number n;  /* try to convert to float */

        if ( !tonumber( obj, &n ) ) { /* cannot convert to float? */
            return 0;    /* not a number */
        }

        if ( luai_numlt( 0, n ) ) { /* if true, float is larger than max integer */
            *p = LUA_MAXINTEGER;

            if ( step < 0 ) {
                *stopnow = 1;
            }
        }
        else {   /* float is smaller than min integer */
            *p = LUA_MININTEGER;

            if ( step >= 0 ) {
                *stopnow = 1;
            }
        }
    }

    return 1;
}


/*
** Finish the table access 'val = t[key]'.
** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
** t[k] entry (which must be nil).
*/
void luaV_finishget( lua_State* L, const TValue* t, TValue* key, StkId val,
                     const TValue* slot ) {
    int loop;  /* counter to avoid infinite loops */
    const TValue* tm;  /* metamethod */

    for ( loop = 0; loop < MAXTAGLOOP; loop++ ) {
        if ( slot == NULL ) { /* 't' is not a table? */
            lua_assert( !ttistable( t ) );
            tm = luaT_gettmbyobj( L, t, TM_INDEX );

            if ( ttisnil( tm ) ) {
                luaG_typeerror( L, t, "index" );    /* no metamethod */
            }

            /* else will try the metamethod */
        }
        else {   /* 't' is a table */
            lua_assert( ttisnil( slot ) );
            tm = fasttm( L, hvalue( t )->metatable, TM_INDEX ); /* table's metamethod */

            if ( tm == NULL ) { /* no metamethod? */
                setnilvalue( val ); /* result is nil */
                return;
            }

            /* else will try the metamethod */
        }

        if ( ttisfunction( tm ) ) { /* is metamethod a function? */
            luaT_callTM( L, tm, t, key, val, 1 ); /* call it */
            return;
        }

        t = tm;  /* else try to access 'tm[key]' */

        if ( luaV_fastget( L, t, key, slot, luaH_get ) ) { /* fast track? */
            setobj2s( L, val, slot ); /* done */
            return;
        }

        /* else repeat (tail call 'luaV_finishget') */
    }

    luaG_runerror( L, "'__index' chain too long; possible loop" );
}


/*
** Finish a table assignment 't[key] = val'.
** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
** to the entry 't[key]', or to 'luaO_nilobject' if there is no such
** entry.  (The value at 'slot' must be nil, otherwise 'luaV_fastset'
** would have done the job.)
*/
void luaV_finishset( lua_State* L, const TValue* t, TValue* key,
                     StkId val, const TValue* slot ) {
    int loop;  /* counter to avoid infinite loops */

    for ( loop = 0; loop < MAXTAGLOOP; loop++ ) {
        const TValue* tm;  /* '__newindex' metamethod */

        if ( slot != NULL ) { /* is 't' a table? */
            Table* h = hvalue( t ); /* save 't' table */
            lua_assert( ttisnil( slot ) ); /* old value must be nil */
            tm = fasttm( L, h->metatable, TM_NEWINDEX ); /* get metamethod */

            if ( tm == NULL ) { /* no metamethod? */
                if ( slot == luaO_nilobject ) { /* no previous entry? */
                    slot = luaH_newkey( L, h, key );    /* create one */
                }

                /* no metamethod and (now) there is an entry with given key */
                setobj2t( L, cast( TValue*, slot ), val ); /* set its new value */
                invalidateTMcache( h );
                luaC_barrierback( L, h, val );
                return;
            }

            /* else will try the metamethod */
        }
        else {   /* not a table; check metamethod */
            if ( ttisnil( tm = luaT_gettmbyobj( L, t, TM_NEWINDEX ) ) ) {
                luaG_typeerror( L, t, "index" );
            }
        }

        /* try the metamethod */
        if ( ttisfunction( tm ) ) {
            luaT_callTM( L, tm, t, key, val, 0 );
            return;
        }

        t = tm;  /* else repeat assignment over 'tm' */

        if ( luaV_fastset( L, t, key, slot, luaH_get, val ) ) {
            return;    /* done */
        }

        /* else loop */
    }

    luaG_runerror( L, "'__newindex' chain too long; possible loop" );
}


/*
** Compare two strings 'ls' x 'rs', returning an integer smaller-equal-
** -larger than zero if 'ls' is smaller-equal-larger than 'rs'.
** The code is a little tricky because it allows '\0' in the strings
** and it uses 'strcoll' (to respect locales) for each segments
** of the strings.
*/
static int l_strcmp( const TString* ls, const TString* rs ) {
    const char* l = getstr( ls );
    size_t ll = tsslen( ls );
    const char* r = getstr( rs );
    size_t lr = tsslen( rs );

    for ( ;; ) { /* for each segment */
        int temp = strcoll( l, r );

        if ( temp != 0 ) { /* not equal? */
            return temp;    /* done */
        }
        else {  /* strings are equal up to a '\0' */
            size_t len = strlen( l ); /* index of first '\0' in both strings */

            if ( len == lr ) { /* 'rs' is finished? */
                return ( len == ll ) ? 0 : 1;    /* check 'ls' */
            }
            else if ( len == ll ) { /* 'ls' is finished? */
                return -1;    /* 'ls' is smaller than 'rs' ('rs' is not finished) */
            }

            /* both strings longer than 'len'; go on comparing after the '\0' */
            len++;
            l += len;
            ll -= len;
            r += len;
            lr -= len;
        }
    }
}


/*
** Check whether integer 'i' is less than float 'f'. If 'i' has an
** exact representation as a float ('l_intfitsf'), compare numbers as
** floats. Otherwise, if 'f' is outside the range for integers, result
** is trivial. Otherwise, compare them as integers. (When 'i' has no
** float representation, either 'f' is "far away" from 'i' or 'f' has
** no precision left for a fractional part; either way, how 'f' is
** truncated is irrelevant.) When 'f' is NaN, comparisons must result
** in false.
*/
static int LTintfloat( lua_Integer i, lua_Number f ) {
#if defined(l_intfitsf)

    if ( !l_intfitsf( i ) ) {
        if ( f >= -cast_num( LUA_MININTEGER ) ) { /* -minint == maxint + 1 */
            return 1;    /* f >= maxint + 1 > i */
        }
        else if ( f > cast_num( LUA_MININTEGER ) ) { /* minint < f <= maxint ? */
            return ( i < cast( lua_Integer, f ) );    /* compare them as integers */
        }
        else { /* f <= minint <= i (or 'f' is NaN)  -->  not(i < f) */
            return 0;
        }
    }

#endif
    return luai_numlt( cast_num( i ), f ); /* compare them as floats */
}


/*
** Check whether integer 'i' is less than or equal to float 'f'.
** See comments on previous function.
*/
static int LEintfloat( lua_Integer i, lua_Number f ) {
#if defined(l_intfitsf)

    if ( !l_intfitsf( i ) ) {
        if ( f >= -cast_num( LUA_MININTEGER ) ) { /* -minint == maxint + 1 */
            return 1;    /* f >= maxint + 1 > i */
        }
        else if ( f >= cast_num( LUA_MININTEGER ) ) { /* minint <= f <= maxint ? */
            return ( i <= cast( lua_Integer, f ) );    /* compare them as integers */
        }
        else { /* f < minint <= i (or 'f' is NaN)  -->  not(i <= f) */
            return 0;
        }
    }

#endif
    return luai_numle( cast_num( i ), f ); /* compare them as floats */
}


/*
** Return 'l < r', for numbers.
*/
static int LTnum( const TValue* l, const TValue* r ) {
    if ( ttisinteger( l ) ) {
        lua_Integer li = ivalue( l );

        if ( ttisinteger( r ) ) {
            return li < ivalue( r );    /* both are integers */
        }
        else { /* 'l' is int and 'r' is float */
            return LTintfloat( li, fltvalue( r ) );    /* l < r ? */
        }
    }
    else {
        lua_Number lf = fltvalue( l ); /* 'l' must be float */

        if ( ttisfloat( r ) ) {
            return luai_numlt( lf, fltvalue( r ) );    /* both are float */
        }
        else if ( luai_numisnan( lf ) ) { /* 'r' is int and 'l' is float */
            return 0;    /* NaN < i is always false */
        }
        else { /* without NaN, (l < r)  <-->  not(r <= l) */
            return !LEintfloat( ivalue( r ), lf );    /* not (r <= l) ? */
        }
    }
}


/*
** Return 'l <= r', for numbers.
*/
static int LEnum( const TValue* l, const TValue* r ) {
    if ( ttisinteger( l ) ) {
        lua_Integer li = ivalue( l );

        if ( ttisinteger( r ) ) {
            return li <= ivalue( r );    /* both are integers */
        }
        else { /* 'l' is int and 'r' is float */
            return LEintfloat( li, fltvalue( r ) );    /* l <= r ? */
        }
    }
    else {
        lua_Number lf = fltvalue( l ); /* 'l' must be float */

        if ( ttisfloat( r ) ) {
            return luai_numle( lf, fltvalue( r ) );    /* both are float */
        }
        else if ( luai_numisnan( lf ) ) { /* 'r' is int and 'l' is float */
            return 0;    /*  NaN <= i is always false */
        }
        else { /* without NaN, (l <= r)  <-->  not(r < l) */
            return !LTintfloat( ivalue( r ), lf );    /* not (r < l) ? */
        }
    }
}


/*
** Main operation less than; return 'l < r'.
*/
int luaV_lessthan( lua_State* L, const TValue* l, const TValue* r ) {
    int res;

    if ( ttisnumber( l ) && ttisnumber( r ) ) { /* both operands are numbers? */
        return LTnum( l, r );
    }
    else if ( ttisstring( l ) && ttisstring( r ) ) { /* both are strings? */
        return l_strcmp( tsvalue( l ), tsvalue( r ) ) < 0;
    }
    else if ( ( res = luaT_callorderTM( L, l, r,
                                        TM_LT ) ) < 0 ) { /* no metamethod? */
        luaG_ordererror( L, l, r );    /* error */
    }

    return res;
}


/*
** Main operation less than or equal to; return 'l <= r'. If it needs
** a metamethod and there is no '__le', try '__lt', based on
** l <= r iff !(r < l) (assuming a total order). If the metamethod
** yields during this substitution, the continuation has to know
** about it (to negate the result of r<l); bit CIST_LEQ in the call
** status keeps that information.
*/
int luaV_lessequal( lua_State* L, const TValue* l, const TValue* r ) {
    int res;

    if ( ttisnumber( l ) && ttisnumber( r ) ) { /* both operands are numbers? */
        return LEnum( l, r );
    }
    else if ( ttisstring( l ) && ttisstring( r ) ) { /* both are strings? */
        return l_strcmp( tsvalue( l ), tsvalue( r ) ) <= 0;
    }
    else if ( ( res = luaT_callorderTM( L, l, r, TM_LE ) ) >= 0 ) { /* try 'le' */
        return res;
    }
    else {  /* try 'lt': */
        L->ci->callstatus |= CIST_LEQ;  /* mark it is doing 'lt' for 'le' */
        res = luaT_callorderTM( L, r, l, TM_LT );
        L->ci->callstatus ^= CIST_LEQ;  /* clear mark */

        if ( res < 0 ) {
            luaG_ordererror( L, l, r );
        }

        return !res;  /* result is negated */
    }
}


/*
** Main operation for equality of Lua values; return 't1 == t2'.
** L == NULL means raw equality (no metamethods)
*/
int luaV_equalobj( lua_State* L, const TValue* t1, const TValue* t2 ) {
    const TValue* tm;

    if ( ttype( t1 ) != ttype( t2 ) ) { /* not the same variant? */
        if ( ttnov( t1 ) != ttnov( t2 ) || ttnov( t1 ) != LUA_TNUMBER ) {
            return 0;    /* only numbers can be equal with different variants */
        }
        else {  /* two numbers with different variants */
            lua_Integer i1, i2;  /* compare them as integers */
            return ( tointeger( t1, &i1 ) && tointeger( t2, &i2 ) && i1 == i2 );
        }
    }

    /* values have same type and same variant */
    switch ( ttype( t1 ) ) {
    case LUA_TNIL:
        return 1;

    case LUA_TNUMINT:
        return ( ivalue( t1 ) == ivalue( t2 ) );

    case LUA_TNUMFLT:
        return luai_numeq( fltvalue( t1 ), fltvalue( t2 ) );

    case LUA_TBOOLEAN:
        return bvalue( t1 ) == bvalue( t2 ); /* true must be 1 !! */

    case LUA_TLIGHTUSERDATA:
        return pvalue( t1 ) == pvalue( t2 );

    case LUA_TLCF:
        return fvalue( t1 ) == fvalue( t2 );

    case LUA_TSHRSTR:
        return eqshrstr( tsvalue( t1 ), tsvalue( t2 ) );

    case LUA_TLNGSTR:
        return luaS_eqlngstr( tsvalue( t1 ), tsvalue( t2 ) );

    case LUA_TUSERDATA: {
        if ( uvalue( t1 ) == uvalue( t2 ) ) {
            return 1;
        }
        else if ( L == NULL ) {
            return 0;
        }

        tm = fasttm( L, uvalue( t1 )->metatable, TM_EQ );

        if ( tm == NULL ) {
            tm = fasttm( L, uvalue( t2 )->metatable, TM_EQ );
        }

        break;  /* will try TM */
    }

    case LUA_TTABLE: {
        if ( hvalue( t1 ) == hvalue( t2 ) ) {
            return 1;
        }
        else if ( L == NULL ) {
            return 0;
        }

        tm = fasttm( L, hvalue( t1 )->metatable, TM_EQ );

        if ( tm == NULL ) {
            tm = fasttm( L, hvalue( t2 )->metatable, TM_EQ );
        }

        break;  /* will try TM */
    }

    default:
        return gcvalue( t1 ) == gcvalue( t2 );
    }

    if ( tm == NULL ) { /* no TM? */
        return 0;    /* objects are different */
    }

    luaT_callTM( L, tm, t1, t2, L->top, 1 ); /* call TM */
    return !l_isfalse( L->top );
}


/* macro used by 'luaV_concat' to ensure that element at 'o' is a string */
#define tostring(L,o)  \
    (ttisstring(o) || (cvt2str(o) && (luaO_tostring(L, o), 1)))

#define isemptystr(o)   (ttisshrstring(o) && tsvalue(o)->shrlen == 0)

/* copy strings in stack from top - n up to top - 1 to buffer */
static void copy2buff( StkId top, int n, char* buff ) {
    size_t tl = 0;  /* size already copied */

    do {
        size_t l = vslen( top - n ); /* length of string being copied */
        memcpy( buff + tl, svalue( top - n ), l * sizeof( char ) );
        tl += l;
    }
    while ( --n > 0 );
}


/*
** Main operation for concatenation: concat 'total' values in the stack,
** from 'L->top - total' up to 'L->top - 1'.
*/
void luaV_concat( lua_State* L, int total ) {
    lua_assert( total >= 2 );

    do {
        StkId top = L->top;
        int n = 2;  /* number of elements handled in this pass (at least 2) */

        if ( !( ttisstring( top - 2 ) || cvt2str( top - 2 ) ) ||
                !tostring( L, top - 1 ) ) {
            luaT_trybinTM( L, top - 2, top - 1, top - 2, TM_CONCAT );
        }
        else if ( isemptystr( top - 1 ) ) { /* second operand is empty? */
            cast_void( tostring( L, top - 2 ) );    /* result is first operand */
        }
        else if ( isemptystr( top - 2 ) ) { /* first operand is an empty string? */
            setobjs2s( L, top - 2, top - 1 ); /* result is second op. */
        }
        else {
            /* at least two non-empty string values; get as many as possible */
            size_t tl = vslen( top - 1 );
            TString* ts;

            /* collect total length and number of strings */
            for ( n = 1; n < total && tostring( L, top - n - 1 ); n++ ) {
                size_t l = vslen( top - n - 1 );

                if ( l >= ( MAX_SIZE / sizeof( char ) ) - tl ) {
                    luaG_runerror( L, "string length overflow" );
                }

                tl += l;
            }

            if ( tl <= LUAI_MAXSHORTLEN ) { /* is result a short string? */
                char buff[LUAI_MAXSHORTLEN];
                copy2buff( top, n, buff ); /* copy strings to buffer */
                ts = luaS_newlstr( L, buff, tl );
            }
            else {   /* long string; copy strings directly to final result */
                ts = luaS_createlngstrobj( L, tl );
                copy2buff( top, n, getstr( ts ) );
            }

            setsvalue2s( L, top - n, ts ); /* create result */
        }

        total -= n - 1; /* got 'n' strings to create 1 new */
        L->top -= n - 1; /* popped 'n' strings and pushed one */
    }
    while ( total > 1 );   /* repeat until only 1 result left */
}


/*
** Main operation 'ra' = #rb'.
*/
void luaV_objlen( lua_State* L, StkId ra, const TValue* rb ) {
    const TValue* tm;

    switch ( ttype( rb ) ) {
    case LUA_TTABLE: {
        Table* h = hvalue( rb );
        tm = fasttm( L, h->metatable, TM_LEN );

        if ( tm ) {
            break;    /* metamethod? break switch to call it */
        }

        setivalue( ra, luaH_getn( h ) ); /* else primitive len */
        return;
    }

    case LUA_TSHRSTR: {
        setivalue( ra, tsvalue( rb )->shrlen );
        return;
    }

    case LUA_TLNGSTR: {
        setivalue( ra, tsvalue( rb )->u.lnglen );
        return;
    }

    default: {  /* try metamethod */
        tm = luaT_gettmbyobj( L, rb, TM_LEN );

        if ( ttisnil( tm ) ) { /* no metamethod? */
            luaG_typeerror( L, rb, "get length of" );
        }

        break;
    }
    }

    luaT_callTM( L, tm, rb, rb, ra, 1 );
}


/*
** Integer division; return 'm // n', that is, floor(m/n).
** C division truncates its result (rounds towards zero).
** 'floor(q) == trunc(q)' when 'q >= 0' or when 'q' is integer,
** otherwise 'floor(q) == trunc(q) - 1'.
*/
lua_Integer luaV_div( lua_State* L, lua_Integer m, lua_Integer n ) {
    if ( l_castS2U( n ) + 1u <= 1u ) { /* special cases: -1 or 0 */
        if ( n == 0 ) {
            luaG_runerror( L, "attempt to divide by zero" );
        }

        return intop( -, 0, m ); /* n==-1; avoid overflow with 0x80000...//-1 */
    }
    else {
        lua_Integer q = m / n;  /* perform C division */

        if ( ( m ^ n ) < 0 && m % n != 0 ) { /* 'm/n' would be negative non-integer? */
            q -= 1;    /* correct result for different rounding */
        }

        return q;
    }
}


/*
** Integer modulus; return 'm % n'. (Assume that C '%' with
** negative operands follows C99 behavior. See previous comment
** about luaV_div.)
*/
lua_Integer luaV_mod( lua_State* L, lua_Integer m, lua_Integer n ) {
    if ( l_castS2U( n ) + 1u <= 1u ) { /* special cases: -1 or 0 */
        if ( n == 0 ) {
            luaG_runerror( L, "attempt to perform 'n%%0'" );
        }

        return 0;   /* m % -1 == 0; avoid overflow with 0x80000...%-1 */
    }
    else {
        lua_Integer r = m % n;

        if ( r != 0 && ( m ^ n ) < 0 ) { /* 'm/n' would be non-integer negative? */
            r += n;    /* correct result for different rounding */
        }

        return r;
    }
}


/* number of bits in an integer */
#define NBITS   cast_int(sizeof(lua_Integer) * CHAR_BIT)

/*
** Shift left operation. (Shift right just negates 'y'.)
*/
lua_Integer luaV_shiftl( lua_Integer x, lua_Integer y ) {
    if ( y < 0 ) { /* shift right? */
        if ( y <= -NBITS ) {
            return 0;
        }
        else {
            return intop( >>, x, -y );
        }
    }
    else {   /* shift left */
        if ( y >= NBITS ) {
            return 0;
        }
        else {
            return intop( <<, x, y );
        }
    }
}


/*
** check whether cached closure in prototype 'p' may be reused, that is,
** whether there is a cached closure with the same upvalues needed by
** new closure to be created.
*/
static LClosure* getcached( Proto* p, UpVal** encup, StkId base ) {
    LClosure* c = p->cache;

    if ( c != NULL ) { /* is there a cached closure? */
        int nup = p->sizeupvalues;
        Upvaldesc* uv = p->upvalues;
        int i;

        for ( i = 0; i < nup; i++ ) { /* check whether it has right upvalues */
            TValue* v = uv[i].instack ? base + uv[i].idx : encup[uv[i].idx]->v;

            if ( c->upvals[i]->v != v ) {
                return NULL;    /* wrong upvalue; cannot reuse closure */
            }
        }
    }

    return c;  /* return cached closure (or NULL if no cached closure) */
}


/*
** create a new Lua closure, push it in the stack, and initialize
** its upvalues. Note that the closure is not cached if prototype is
** already black (which means that 'cache' was already cleared by the
** GC).
*/
static void pushclosure( lua_State* L, Proto* p, UpVal** encup, StkId base,
                         StkId ra ) {
    int nup = p->sizeupvalues;
    Upvaldesc* uv = p->upvalues;
    int i;
    LClosure* ncl = luaF_newLclosure( L, nup );
    ncl->p = p;
    setclLvalue( L, ra, ncl ); /* anchor new closure in stack */

    for ( i = 0; i < nup; i++ ) { /* fill in its upvalues */
        if ( uv[i].instack ) { /* upvalue refers to local variable? */
            ncl->upvals[i] = luaF_findupval( L, base + uv[i].idx );
        }
        else { /* get upvalue from enclosing function */
            ncl->upvals[i] = encup[uv[i].idx];
        }

        ncl->upvals[i]->refcount++;
        /* new closure is white, so we do not need a barrier here */
    }

    if ( !isblack( p ) ) { /* cache will not break GC invariant? */
        p->cache = ncl;    /* save it on cache for reuse */
    }
}


/*
** finish execution of an opcode interrupted by an yield
*/
void luaV_finishOp( lua_State* L ) {
    CallInfo* ci = L->ci;
    StkId base = ci->u.l.base;
    Instruction inst = *( ci->u.l.savedpc - 1 ); /* interrupted instruction */
    OpCode op = GET_OPCODE( inst );

    switch ( op ) { /* finish its execution */
    case OP_ADD:
    case OP_SUB:
    case OP_MUL:
    case OP_DIV:
    case OP_IDIV:
    case OP_BAND:
    case OP_BOR:
    case OP_BXOR:
    case OP_SHL:
    case OP_SHR:
    case OP_MOD:
    case OP_POW:
    case OP_UNM:
    case OP_BNOT:
    case OP_LEN:
    case OP_GETTABUP:
    case OP_GETTABLE:
    case OP_SELF: {
        setobjs2s( L, base + GETARG_A( inst ), --L->top );
        break;
    }

    case OP_LE:
    case OP_LT:
    case OP_EQ: {
        int res = !l_isfalse( L->top - 1 );
        L->top--;

        if ( ci->callstatus & CIST_LEQ ) { /* "<=" using "<" instead? */
            lua_assert( op == OP_LE );
            ci->callstatus ^= CIST_LEQ;  /* clear mark */
            res = !res;  /* negate result */
        }

        lua_assert( GET_OPCODE( *ci->u.l.savedpc ) == OP_JMP );

        if ( res != GETARG_A( inst ) ) { /* condition failed? */
            ci->u.l.savedpc++;    /* skip jump instruction */
        }

        break;
    }

    case OP_CONCAT: {
        StkId top = L->top - 1;  /* top when 'luaT_trybinTM' was called */
        int b = GETARG_B( inst );    /* first element to concatenate */
        int total = cast_int( top - 1 - ( base + b ) ); /* yet to concatenate */
        setobj2s( L, top - 2, top ); /* put TM result in proper position */

        if ( total > 1 ) { /* are there elements to concat? */
            L->top = top - 1;  /* top is one after last element (at top-2) */
            luaV_concat( L, total ); /* concat them (may yield again) */
        }

        /* move final result to final position */
        setobj2s( L, ci->u.l.base + GETARG_A( inst ), L->top - 1 );
        L->top = ci->top;  /* restore top */
        break;
    }

    case OP_TFORCALL: {
        lua_assert( GET_OPCODE( *ci->u.l.savedpc ) == OP_TFORLOOP );
        L->top = ci->top;  /* correct top */
        break;
    }

    case OP_CALL: {
        if ( GETARG_C( inst ) - 1 >= 0 ) { /* nresults >= 0? */
            L->top = ci->top;    /* adjust results */
        }

        break;
    }

    case OP_TAILCALL:
    case OP_SETTABUP:
    case OP_SETTABLE:
        break;

    default:
        lua_assert( 0 );
    }
}




/*
** {==================================================================
** Function 'luaV_execute': main interpreter loop
** ===================================================================
*/


/*
** some macros for common tasks in 'luaV_execute'
*/


#define RA(i)   (base+GETARG_A(i))
#define RB(i)   check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
#define RC(i)   check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
#define RKB(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
    ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
#define RKC(i)  check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
    ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))


/* execute a jump instruction */
#define dojump(ci,i,e) \
  { int a = GETARG_A(i); \
    if (a != 0) luaF_close(L, ci->u.l.base + a - 1); \
    ci->u.l.savedpc += GETARG_sBx(i) + e; }

/* for test instructions, execute the jump instruction that follows it */
#define donextjump(ci)  { i = *ci->u.l.savedpc; dojump(ci, i, 1); }


#define Protect(x)  { {x;}; base = ci->u.l.base; }

#define checkGC(L,c)  \
    { luaC_condGC(L, L->top = (c),  /* limit of live values */ \
                         Protect(L->top = ci->top));  /* restore top */ \
           luai_threadyield(L); }


/* fetch an instruction and prepare its execution */
#define vmfetch()   { \
  i = *(ci->u.l.savedpc++); \
  if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) \
    Protect(luaG_traceexec(L)); \
  ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
  lua_assert(base == ci->u.l.base); \
  lua_assert(base <= L->top && L->top < L->stack + L->stacksize); \
}

#define vmdispatch(o)   switch(o)
#define vmcase(l)   case l:
#define vmbreak     break


/*
** copy of 'luaV_gettable', but protecting the call to potential
** metamethod (which can reallocate the stack)
*/
#define gettableProtected(L,t,k,v)  { const TValue *slot; \
  if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \
  else Protect(luaV_finishget(L,t,k,v,slot)); }


/* same for 'luaV_settable' */
#define settableProtected(L,t,k,v) { const TValue *slot; \
  if (!luaV_fastset(L,t,k,slot,luaH_get,v)) \
    Protect(luaV_finishset(L,t,k,v,slot)); }



void luaV_execute( lua_State* L ) {
    CallInfo* ci = L->ci;
    LClosure* cl;
    TValue* k;
    StkId base;
    ci->callstatus |= CIST_FRESH;  /* fresh invocation of 'luaV_execute" */
newframe:  /* reentry point when frame changes (call/return) */
    lua_assert( ci == L->ci );
    cl = clLvalue( ci->func ); /* local reference to function's closure */
    k = cl->p->k;  /* local reference to function's constant table */
    base = ci->u.l.base;  /* local copy of function's base */

    /* main loop of interpreter */
    for ( ;; ) {
        Instruction i;
        StkId ra;
        vmfetch();
        vmdispatch( GET_OPCODE( i ) ) {
            vmcase( OP_MOVE ) {
                setobjs2s( L, ra, RB( i ) );
                vmbreak;
            }
            vmcase( OP_LOADK ) {
                TValue* rb = k + GETARG_Bx( i );
                setobj2s( L, ra, rb );
                vmbreak;
            }
            vmcase( OP_LOADKX ) {
                TValue* rb;
                lua_assert( GET_OPCODE( *ci->u.l.savedpc ) == OP_EXTRAARG );
                rb = k + GETARG_Ax( *ci->u.l.savedpc++ );
                setobj2s( L, ra, rb );
                vmbreak;
            }
            vmcase( OP_LOADBOOL ) {
                setbvalue( ra, GETARG_B( i ) );

                if ( GETARG_C( i ) ) {
                    ci->u.l.savedpc++;    /* skip next instruction (if C) */
                }

                vmbreak;
            }
            vmcase( OP_LOADNIL ) {
                int b = GETARG_B( i );

                do {
                    setnilvalue( ra++ );
                }
                while ( b-- );

                vmbreak;
            }
            vmcase( OP_GETUPVAL ) {
                int b = GETARG_B( i );
                setobj2s( L, ra, cl->upvals[b]->v );
                vmbreak;
            }
            vmcase( OP_GETTABUP ) {
                TValue* upval = cl->upvals[GETARG_B( i )]->v;
                TValue* rc = RKC( i );
                gettableProtected( L, upval, rc, ra );
                vmbreak;
            }
            vmcase( OP_GETTABLE ) {
                StkId rb = RB( i );
                TValue* rc = RKC( i );
                gettableProtected( L, rb, rc, ra );
                vmbreak;
            }
            vmcase( OP_SETTABUP ) {
                TValue* upval = cl->upvals[GETARG_A( i )]->v;
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                settableProtected( L, upval, rb, rc );
                vmbreak;
            }
            vmcase( OP_SETUPVAL ) {
                UpVal* uv = cl->upvals[GETARG_B( i )];
                setobj( L, uv->v, ra );
                luaC_upvalbarrier( L, uv );
                vmbreak;
            }
            vmcase( OP_SETTABLE ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                settableProtected( L, ra, rb, rc );
                vmbreak;
            }
            vmcase( OP_NEWTABLE ) {
                int b = GETARG_B( i );
                int c = GETARG_C( i );
                Table* t = luaH_new( L );
                sethvalue( L, ra, t );

                if ( b != 0 || c != 0 ) {
                    luaH_resize( L, t, luaO_fb2int( b ), luaO_fb2int( c ) );
                }

                checkGC( L, ra + 1 );
                vmbreak;
            }
            vmcase( OP_SELF ) {
                const TValue* aux;
                StkId rb = RB( i );
                TValue* rc = RKC( i );
                TString* key = tsvalue( rc ); /* key must be a string */
                setobjs2s( L, ra + 1, rb );

                if ( luaV_fastget( L, rb, key, aux, luaH_getstr ) ) {
                    setobj2s( L, ra, aux );
                }
                else {
                    Protect( luaV_finishget( L, rb, rc, ra, aux ) );
                }

                vmbreak;
            }
            vmcase( OP_ADD ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( ttisinteger( rb ) && ttisinteger( rc ) ) {
                    lua_Integer ib = ivalue( rb );
                    lua_Integer ic = ivalue( rc );
                    setivalue( ra, intop( +, ib, ic ) );
                }
                else if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_numadd( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_ADD ) );
                }

                vmbreak;
            }
            vmcase( OP_SUB ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( ttisinteger( rb ) && ttisinteger( rc ) ) {
                    lua_Integer ib = ivalue( rb );
                    lua_Integer ic = ivalue( rc );
                    setivalue( ra, intop( -, ib, ic ) );
                }
                else if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_numsub( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_SUB ) );
                }

                vmbreak;
            }
            vmcase( OP_MUL ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( ttisinteger( rb ) && ttisinteger( rc ) ) {
                    lua_Integer ib = ivalue( rb );
                    lua_Integer ic = ivalue( rc );
                    setivalue( ra, intop( *, ib, ic ) );
                }
                else if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_nummul( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_MUL ) );
                }

                vmbreak;
            }
            vmcase( OP_DIV ) { /* float division (always with floats) */
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_numdiv( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_DIV ) );
                }

                vmbreak;
            }
            vmcase( OP_BAND ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Integer ib;
                lua_Integer ic;

                if ( tointeger( rb, &ib ) && tointeger( rc, &ic ) ) {
                    setivalue( ra, intop( &, ib, ic ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_BAND ) );
                }

                vmbreak;
            }
            vmcase( OP_BOR ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Integer ib;
                lua_Integer ic;

                if ( tointeger( rb, &ib ) && tointeger( rc, &ic ) ) {
                    setivalue( ra, intop( |, ib, ic ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_BOR ) );
                }

                vmbreak;
            }
            vmcase( OP_BXOR ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Integer ib;
                lua_Integer ic;

                if ( tointeger( rb, &ib ) && tointeger( rc, &ic ) ) {
                    setivalue( ra, intop( ^, ib, ic ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_BXOR ) );
                }

                vmbreak;
            }
            vmcase( OP_SHL ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Integer ib;
                lua_Integer ic;

                if ( tointeger( rb, &ib ) && tointeger( rc, &ic ) ) {
                    setivalue( ra, luaV_shiftl( ib, ic ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_SHL ) );
                }

                vmbreak;
            }
            vmcase( OP_SHR ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Integer ib;
                lua_Integer ic;

                if ( tointeger( rb, &ib ) && tointeger( rc, &ic ) ) {
                    setivalue( ra, luaV_shiftl( ib, -ic ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_SHR ) );
                }

                vmbreak;
            }
            vmcase( OP_MOD ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( ttisinteger( rb ) && ttisinteger( rc ) ) {
                    lua_Integer ib = ivalue( rb );
                    lua_Integer ic = ivalue( rc );
                    setivalue( ra, luaV_mod( L, ib, ic ) );
                }
                else if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    lua_Number m;
                    luai_nummod( L, nb, nc, m );
                    setfltvalue( ra, m );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_MOD ) );
                }

                vmbreak;
            }
            vmcase( OP_IDIV ) { /* floor division */
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( ttisinteger( rb ) && ttisinteger( rc ) ) {
                    lua_Integer ib = ivalue( rb );
                    lua_Integer ic = ivalue( rc );
                    setivalue( ra, luaV_div( L, ib, ic ) );
                }
                else if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_numidiv( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_IDIV ) );
                }

                vmbreak;
            }
            vmcase( OP_POW ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                lua_Number nb;
                lua_Number nc;

                if ( tonumber( rb, &nb ) && tonumber( rc, &nc ) ) {
                    setfltvalue( ra, luai_numpow( L, nb, nc ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rc, ra, TM_POW ) );
                }

                vmbreak;
            }
            vmcase( OP_UNM ) {
                TValue* rb = RB( i );
                lua_Number nb;

                if ( ttisinteger( rb ) ) {
                    lua_Integer ib = ivalue( rb );
                    setivalue( ra, intop( -, 0, ib ) );
                }
                else if ( tonumber( rb, &nb ) ) {
                    setfltvalue( ra, luai_numunm( L, nb ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rb, ra, TM_UNM ) );
                }

                vmbreak;
            }
            vmcase( OP_BNOT ) {
                TValue* rb = RB( i );
                lua_Integer ib;

                if ( tointeger( rb, &ib ) ) {
                    setivalue( ra, intop( ^, ~l_castS2U( 0 ), ib ) );
                }
                else {
                    Protect( luaT_trybinTM( L, rb, rb, ra, TM_BNOT ) );
                }

                vmbreak;
            }
            vmcase( OP_NOT ) {
                TValue* rb = RB( i );
                int res = l_isfalse( rb ); /* next assignment may change this value */
                setbvalue( ra, res );
                vmbreak;
            }
            vmcase( OP_LEN ) {
                Protect( luaV_objlen( L, ra, RB( i ) ) );
                vmbreak;
            }
            vmcase( OP_CONCAT ) {
                int b = GETARG_B( i );
                int c = GETARG_C( i );
                StkId rb;
                L->top = base + c + 1;  /* mark the end of concat operands */
                Protect( luaV_concat( L, c - b + 1 ) );
                ra = RA( i ); /* 'luaV_concat' may invoke TMs and move the stack */
                rb = base + b;
                setobjs2s( L, ra, rb );
                checkGC( L, ( ra >= rb ? ra + 1 : rb ) );
                L->top = ci->top;  /* restore top */
                vmbreak;
            }
            vmcase( OP_JMP ) {
                dojump( ci, i, 0 );
                vmbreak;
            }
            vmcase( OP_EQ ) {
                TValue* rb = RKB( i );
                TValue* rc = RKC( i );
                Protect(

                    if ( luaV_equalobj( L, rb, rc ) != GETARG_A( i ) )
                    ci->u.l.savedpc++;
                else {
                    donextjump( ci );
                    }
                )
                vmbreak;
            }
            vmcase( OP_LT ) {
                Protect(

                    if ( luaV_lessthan( L, RKB( i ), RKC( i ) ) != GETARG_A( i ) )
                    ci->u.l.savedpc++;
                else {
                    donextjump( ci );
                    }
                )
                vmbreak;
            }
            vmcase( OP_LE ) {
                Protect(

                    if ( luaV_lessequal( L, RKB( i ), RKC( i ) ) != GETARG_A( i ) )
                    ci->u.l.savedpc++;
                else {
                    donextjump( ci );
                    }
                )
                vmbreak;
            }
            vmcase( OP_TEST ) {
                if ( GETARG_C( i ) ? l_isfalse( ra ) : !l_isfalse( ra ) ) {
                    ci->u.l.savedpc++;
                }
                else {
                    donextjump( ci );
                }

                vmbreak;
            }
            vmcase( OP_TESTSET ) {
                TValue* rb = RB( i );

                if ( GETARG_C( i ) ? l_isfalse( rb ) : !l_isfalse( rb ) ) {
                    ci->u.l.savedpc++;
                }
                else {
                    setobjs2s( L, ra, rb );
                    donextjump( ci );
                }

                vmbreak;
            }
            vmcase( OP_CALL ) {
                int b = GETARG_B( i );
                int nresults = GETARG_C( i ) - 1;

                if ( b != 0 ) {
                    L->top = ra + b;    /* else previous instruction set top */
                }

                if ( luaD_precall( L, ra, nresults ) ) { /* C function? */
                    if ( nresults >= 0 ) {
                        L->top = ci->top;    /* adjust results */
                    }

                    Protect( ( void )0 ); /* update 'base' */
                }
                else {   /* Lua function */
                    ci = L->ci;
                    goto newframe;  /* restart luaV_execute over new Lua function */
                }

                vmbreak;
            }
            vmcase( OP_TAILCALL ) {
                int b = GETARG_B( i );

                if ( b != 0 ) {
                    L->top = ra + b;    /* else previous instruction set top */
                }

                lua_assert( GETARG_C( i ) - 1 == LUA_MULTRET );

                if ( luaD_precall( L, ra, LUA_MULTRET ) ) { /* C function? */
                    Protect( ( void )0 ); /* update 'base' */
                }
                else {
                    /* tail call: put called frame (n) in place of caller one (o) */
                    CallInfo* nci = L->ci;  /* called frame */
                    CallInfo* oci = nci->previous;  /* caller frame */
                    StkId nfunc = nci->func;  /* called function */
                    StkId ofunc = oci->func;  /* caller function */
                    /* last stack slot filled by 'precall' */
                    StkId lim = nci->u.l.base + getproto( nfunc )->numparams;
                    int aux;

                    /* close all upvalues from previous call */
                    if ( cl->p->sizep > 0 ) {
                        luaF_close( L, oci->u.l.base );
                    }

                    /* move new frame into old one */
                    for ( aux = 0; nfunc + aux < lim; aux++ ) {
                        setobjs2s( L, ofunc + aux, nfunc + aux );
                    }

                    oci->u.l.base = ofunc + ( nci->u.l.base - nfunc ); /* correct base */
                    oci->top = L->top = ofunc + ( L->top - nfunc ); /* correct top */
                    oci->u.l.savedpc = nci->u.l.savedpc;
                    oci->callstatus |= CIST_TAIL;  /* function was tail called */
                    ci = L->ci = oci;  /* remove new frame */
                    lua_assert( L->top == oci->u.l.base + getproto( ofunc )->maxstacksize );
                    goto newframe;  /* restart luaV_execute over new Lua function */
                }

                vmbreak;
            }
            vmcase( OP_RETURN ) {
                int b = GETARG_B( i );

                if ( cl->p->sizep > 0 ) {
                    luaF_close( L, base );
                }

                b = luaD_poscall( L, ci, ra, ( b != 0 ? b - 1 : cast_int( L->top - ra ) ) );

                if ( ci->callstatus & CIST_FRESH ) { /* local 'ci' still from callee */
                    return;    /* external invocation: return */
                }
                else {  /* invocation via reentry: continue execution */
                    ci = L->ci;

                    if ( b ) {
                        L->top = ci->top;
                    }

                    lua_assert( isLua( ci ) );
                    lua_assert( GET_OPCODE( *( ( ci )->u.l.savedpc - 1 ) ) == OP_CALL );
                    goto newframe;  /* restart luaV_execute over new Lua function */
                }
            }
            vmcase( OP_FORLOOP ) {
                if ( ttisinteger( ra ) ) { /* integer loop? */
                    lua_Integer step = ivalue( ra + 2 );
                    lua_Integer idx = intop( +, ivalue( ra ), step ); /* increment index */
                    lua_Integer limit = ivalue( ra + 1 );

                    if ( ( 0 < step ) ? ( idx <= limit ) : ( limit <= idx ) ) {
                        ci->u.l.savedpc += GETARG_sBx( i ); /* jump back */
                        chgivalue( ra, idx ); /* update internal index... */
                        setivalue( ra + 3, idx ); /* ...and external index */
                    }
                }
                else {   /* floating loop */
                    lua_Number step = fltvalue( ra + 2 );
                    lua_Number idx = luai_numadd( L, fltvalue( ra ), step ); /* inc. index */
                    lua_Number limit = fltvalue( ra + 1 );

                    if ( luai_numlt( 0, step ) ? luai_numle( idx, limit )
                            : luai_numle( limit, idx ) ) {
                        ci->u.l.savedpc += GETARG_sBx( i ); /* jump back */
                        chgfltvalue( ra, idx ); /* update internal index... */
                        setfltvalue( ra + 3, idx ); /* ...and external index */
                    }
                }

                vmbreak;
            }
            vmcase( OP_FORPREP ) {
                TValue* init = ra;
                TValue* plimit = ra + 1;
                TValue* pstep = ra + 2;
                lua_Integer ilimit;
                int stopnow;

                if ( ttisinteger( init ) && ttisinteger( pstep ) &&
                        forlimit( plimit, &ilimit, ivalue( pstep ), &stopnow ) ) {
                    /* all values are integer */
                    lua_Integer initv = ( stopnow ? 0 : ivalue( init ) );
                    setivalue( plimit, ilimit );
                    setivalue( init, intop( -, initv, ivalue( pstep ) ) );
                }
                else {   /* try making all values floats */
                    lua_Number ninit;
                    lua_Number nlimit;
                    lua_Number nstep;

                    if ( !tonumber( plimit, &nlimit ) ) {
                        luaG_runerror( L, "'for' limit must be a number" );
                    }

                    setfltvalue( plimit, nlimit );

                    if ( !tonumber( pstep, &nstep ) ) {
                        luaG_runerror( L, "'for' step must be a number" );
                    }

                    setfltvalue( pstep, nstep );

                    if ( !tonumber( init, &ninit ) ) {
                        luaG_runerror( L, "'for' initial value must be a number" );
                    }

                    setfltvalue( init, luai_numsub( L, ninit, nstep ) );
                }

                ci->u.l.savedpc += GETARG_sBx( i );
                vmbreak;
            }
            vmcase( OP_TFORCALL ) {
                StkId cb = ra + 3;  /* call base */
                setobjs2s( L, cb + 2, ra + 2 );
                setobjs2s( L, cb + 1, ra + 1 );
                setobjs2s( L, cb, ra );
                L->top = cb + 3;  /* func. + 2 args (state and index) */
                Protect( luaD_call( L, cb, GETARG_C( i ) ) );
                L->top = ci->top;
                i = *( ci->u.l.savedpc++ ); /* go to next instruction */
                ra = RA( i );
                lua_assert( GET_OPCODE( i ) == OP_TFORLOOP );
                goto l_tforloop;
            }
            vmcase( OP_TFORLOOP ) {
l_tforloop:

                if ( !ttisnil( ra + 1 ) ) { /* continue loop? */
                    setobjs2s( L, ra, ra + 1 ); /* save control variable */
                    ci->u.l.savedpc += GETARG_sBx( i ); /* jump back */
                }

                vmbreak;
            }
            vmcase( OP_SETLIST ) {
                int n = GETARG_B( i );
                int c = GETARG_C( i );
                unsigned int last;
                Table* h;

                if ( n == 0 ) {
                    n = cast_int( L->top - ra ) - 1;
                }

                if ( c == 0 ) {
                    lua_assert( GET_OPCODE( *ci->u.l.savedpc ) == OP_EXTRAARG );
                    c = GETARG_Ax( *ci->u.l.savedpc++ );
                }

                h = hvalue( ra );
                last = ( ( c - 1 ) * LFIELDS_PER_FLUSH ) + n;

                if ( last > h->sizearray ) { /* needs more space? */
                    luaH_resizearray( L, h, last );    /* preallocate it at once */
                }

                for ( ; n > 0; n-- ) {
                    TValue* val = ra + n;
                    luaH_setint( L, h, last--, val );
                    luaC_barrierback( L, h, val );
                }

                L->top = ci->top;  /* correct top (in case of previous open call) */
                vmbreak;
            }
            vmcase( OP_CLOSURE ) {
                Proto* p = cl->p->p[GETARG_Bx( i )];
                LClosure* ncl = getcached( p, cl->upvals, base ); /* cached closure */

                if ( ncl == NULL ) { /* no match? */
                    pushclosure( L, p, cl->upvals, base, ra );    /* create a new one */
                }
                else {
                    setclLvalue( L, ra, ncl );    /* push cashed closure */
                }

                checkGC( L, ra + 1 );
                vmbreak;
            }
            vmcase( OP_VARARG ) {
                int b = GETARG_B( i ) - 1; /* required results */
                int j;
                int n = cast_int( base - ci->func ) - cl->p->numparams - 1;

                if ( n < 0 ) { /* less arguments than parameters? */
                    n = 0;    /* no vararg arguments */
                }

                if ( b < 0 ) { /* B == 0? */
                    b = n;  /* get all var. arguments */
                    Protect( luaD_checkstack( L, n ) );
                    ra = RA( i ); /* previous call may change the stack */
                    L->top = ra + n;
                }

                for ( j = 0; j < b && j < n; j++ ) {
                    setobjs2s( L, ra + j, base - n + j );
                }

                for ( ; j < b; j++ ) { /* complete required results with nil */
                    setnilvalue( ra + j );
                }

                vmbreak;
            }
            vmcase( OP_EXTRAARG ) {
                lua_assert( 0 );
                vmbreak;
            }
        }
    }
}

/* }================================================================== */

